This invention relates to a dielectric resonator controlled or stabilized oscillator with frequency multiplication.
Dielectric resonator controlled oscillators are described in a tutorial review which was contributed by James K. Ploudre et al to IEEE Transactions on Microwave Theory and Techniques, Volume MTT-29, No. 8 (August 1981), pages 754 to 770, under the title of "Application of Dielectric Resonators in Microwave Components". According to the Ploudre et al review, page 763, the dielectric resonator controlled oscillators are advantageous of small size, simple structure, low cost, insensitivity to mechanical vibration and electric power transients, tone-free output, low noise, or direct operation between 1 GHz and 12 GHz even without frequency multiplication.
In the manner which will later be described more in detail, a conventional dielectric resonator controlled oscillator with frequency multiplication comprises a field effect transistor (FET) having a gate electrode, a source electrode, and a drain electrode and a gate-side circuit which comprises a transmission line or microstrip line having a first end terminated by a resistor and a second end connected to the gate electrode and a dielectric resonator electromagnetically coupled to the line so that the gate-side circuit be tuned to a fundamental oscillation generated by the oscillator. Between the gate and the source electrodes, the field effect transistor has a nonlinear diode characteristic which multiplies the fundamental oscillation in frequency into a higher harmonic or frequency multiplied oscillation. With the conventional dielectric resonator controlled oscillator, a loss has been inevitably caused to the higher harmonic oscillation. The conventional dielectric resonator controlled oscillator therefore has a low oscillation efficiency for the higher harmonic oscillation.
As will also be described later, an improved conventional dielectric resonator controlled oscillator is disclosed in European Patent Application No. 83 103 122.4 which was filed by Nippon Electric Co., Ltd., namely, NEC Corporation, assignee from Mizumura, Motoo et al, the inventors, and was published 05.10.83 under Publication No. 0 090 414. In the improved conventional oscillator, the above-mentioned first end is an open end. It has now been found that the improved conventional oscillator has an electric characteristic which has a room for further improvement.